This invention generally relates to an apparatus for producing food products, and more particularly, to an apparatus for producing food products in two layers in which an outer material envelops an inner material.
Well known in the prior art are apparatuses for producing food products in two layers, such as a Chinese bun, in which an inner food material (xe2x80x9cfillingxe2x80x9d), e.g., a bean-paste, is enveloped by an outer food material (xe2x80x9ccasingxe2x80x9d), e.g., a dough.
Such an apparatus is disclosed in Japanese Utility Model No. 4-43032, assigned to the Applicant. The apparatus includes a filling feeder for feeding a filling, a casing feeder for feeding a casing, a pair of dual screw conveyors, a pair of vane pumps, and a double nozzle. The screw conveyors separately operate such that each one receives the corresponding filling or casing from the corresponding feeder and transports it to the corresponding vane pump. The vane pump measures the transported material and continuously feeds it to the double nozzle for extruding an elongated and enveloped food product in which the outer material from the casing feeder envelops the inner material from the filling feeder. Each screw conveyor includes a rotatable screw or spiral that extends from under the corresponding feeder to an opening of the double nozzle such that the inner and outer food materials are propelled from the feeders to the double nozzle by the rotations of the screws.
Typically, the elongated product that is extruded from the double nozzle is then fed to a cutting mechanism that continuously cuts the elongated product to produce, e.g., rounded or slightly rounded, enveloped products, in each of which the casing envelops the filling. The rounded and enveloped products, which are fed from the cutting mechanism, then are set on a linear conveyor, e.g., a belt conveyor.
The yield of the rounded and enveloped products can be increased by using two or more double nozzles and corresponding cutting mechanisms, and corresponding pairs of screw conveyors, as shown in Japanese Patent Early-Publication No. 10-99025A, assigned to the applicant.
In the layout of a manufacturing line, each screw conveyor for the filling or the casing is located within an elongated housing, which is arranged such that the rotating shaft of the screw is orthogonal to the direction that the linear conveyor travels.
For example, if one wishes to feed two rows of the rounded enveloped products in parallel on the linear conveyor at the same time, two double nozzles, two dual vane pumps, and two dual cutting mechanisms are provided, above the linear conveyor, one on each side. Two pairs of elongated housings that each includes a screw conveyor are also provided.
To carry out this purpose, some examples of layouts of the linear conveyor and the two pairs of the elongated housings have been proposed.
In one layout, the linear conveyor and the two pairs of the elongated housings are arranged such that they form a cruciform, in which one pair of the elongated housings is located at the right side of the linear conveyor, while the opposed pair of the elongated housings is located at the left side. Unfortunately, this layout needs a wide space at each side of the linear conveyor, since the elongated housings are projected therefrom to form the cruciform. Further, food materials to be fed to the screw conveyors should be supplied from both sides of the linear conveyor and thus supply routes and the associated tasks can be complicated.
As an alternative layout, each of the elongated housings accommodates one screw conveyor, and the housings are arranged in parallel at one side of the linear conveyor. With this layout, the space at the other side of the linear conveyor can be reduced. Similarly, the supply routes and the associated tasks can be made simpler. However, because two double nozzles are arranged in parallel above the linear conveyor, one on the right and one on the left, the distance that the food materials to be transferred between the one pair of the screw conveyors and the double nozzle of the pair differs from that between the other pair of the screw conveyors and its double nozzle. As a result, the quantities of the elongated products extruded from the double nozzles may be unbalanced.
Considering the layouts of the rotating shaft of the screw of each screw conveyor and the rotating shaft of the corresponding vane pump, their rotating shafts may be offset and disposed at different levels, in parallel. Unfortunately, the height of any apparatus that employs such upper and lower offset shafts must be increased.
As an alternative design to avoid this problem, the rotating shaft of the screw of the screw conveyor and the rotating shaft of the corresponding vane pump may be disposed at the same level by connecting them by a bent piping. Although this alternative design can reduce the height of the apparatus, the direction of the flow of the food material from each screw should be turned toward the corresponding vane pump at the bent piping. Such a bent piping or turning passage may produce undesirable kneading of the food material due to the frictional resistances of the inner walls of it.
About the aspect of the components and the construction of the conventional apparatus, the number of vane pumps and the number of screw conveyors are in a one-to-one correspondence. Therefore, if a plurality of the double nozzles are used, the corresponding number of the vane pumps, and thus the corresponding number of the screw conveyors, should be employed. Consequently, the entire construction of the apparatus would be complicated. To simplify the construction of the apparatus, it is also proposed that a dual screw conveyor, which includes a pair of screws or spirals, can be used instead of each pair of the screw conveyors. However, this construction also involves the above problem of the undesirable kneading.
Accordingly, there is need in the art for a compact and simple apparatus that mass produces produces double-layered food products without any undesirable kneading.
In the conventional apparatuses described above, another problem also arises regarding the vane pumps. Each vane pump includes a radial arrangement of vanes situated at spaced circumferential points about the rotating shaft of the vane pump such that each space, which is defined by a pair of adjacent vanes, receives a mass of the food material. However, the spaces defined by each adjacent vane may often fill with unbalanced quantities of the food materials.
Accordingly, there is also a need in the art for an improvement that can smoothly feed a fixed quantity of food material into the corresponding double nozzle.
The present invention provides an apparatus for producing enveloped food products in which an outer food material envelops an inner food material. The apparatus includes a linear conveyor, having a given width and length, for conveying the enveloped food products to be set on the linear conveyor in multiple rows across the width of the linear conveyor, in the traveling direction, i.e., along the length of the linear conveyor. The apparatus also includes multiple units, located above the linear conveyor, each for producing enveloped food products corresponding to a separate row of each of the multiple rows of the enveloped food products on the linear conveyor. The multiple-units are arranged in parallel with each other such that their lengths are in the traveling direction of the linear conveyor.
Each unit of the multiple-units includes 1) a first feeding means, having an outlet for receiving the inner food material and for feeding out the inner food material from the outlet, 2) a second feeding means, having an outlet for receiving the outer food material and for feeding out the outer food material from the outlet of the second feeding means, wherein the second feeding means is opposed to the first feeding means, 3) a pair of vane pumps, one of which is provided for the inner food material and the other of which is provided for the outer food material, wherein each vane pump has an inlet near the corresponding outlet of the corresponding feeding means and an opposed vent and wherein each vane pump receives the corresponding food material from the corresponding outlet of the corresponding feeding means at the inlet of the vane pump, and continuously pumps out the received food material from the opposed outlet of the vane pump in a predetermined quantity, 4) enveloping means, located between the opposed outlets of the vane pumps, for causing the inner food material from the one vane pump to envelop the outer food material from the other vane pump so as to form an elongated product in which the outer-food material envelops the inner food materials and for extruding the elongated product from the adhering means, and 5) cutting means, located under the enveloping means, for cutting the elongated product so as to form a plurality of enveloped food products wherein in each product the outer food material envelops the inner food material, and for causing the cut products on the linear conveyor to drop such that the dropped and cut products form a predetermined row in the multiple rows of the enveloped food products on the linear conveyor.
Preferably, two or more units may form an integrated unit. In the preferred embodiments, each feeding means has a rotating screw or spiral for propelling the corresponding food material to the outlet of the feeding means. The rotating shaft of the rotating screw may be provided horizontally. In this case, the rotating screw and the pump can be located at the same level. Alternatively, the rotating shaft of the rotating screw may be provided vertically.
In the preferred embodiment, each vane pump has a vertical rotating shaft.
Preferably, the enveloping means and the cutting means are located at the longitudinal center of the unit. In this case, the multiple units may be arranged such that the points where the enveloped food products drop on the linear conveyor from the cutting means are substantially aligned on a straight line across the width of the linear conveyor.